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  • Analytical Chemistry and Spectroscopy  (3)
  • Key words: Silver crucian carp — Gynogenesis — Gonochoristic reproduction — Sex evolution — Genetic recombination — RAPD markers  (1)
  • brittle matrix  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Genetic Evidence for Gonochoristic Reproduction in Gynogenetic Silver Crucian Carp (Carassius auratus gibelio Bloch) as Revealed by RAPD Assays (2000)
    Springer
    Journal of molecular evolution 51 (2000), S. 498-506 
    Details
    ISSN: 1432-1432
    Keywords: Key words: Silver crucian carp — Gynogenesis — Gonochoristic reproduction — Sex evolution — Genetic recombination — RAPD markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Sex evolution has been a debating focus in evolutionary genetics. In lower vertebrates of reptiles, amphibians, and fish, a species or a bioform reproduces either sexually or asexually but never both. A few species were found to consist of all females in fish. These all-female species can propagate by asexual reproduction modes, such as gynogenesis and hybridogenesis. However, the coexistence of sexuality and asexuality in a single species was recently noted only in a cyprinid fish silver crucian carp, Carassius auratus gibelio. This fish had been demonstrated to be capable of gynogenesis stimulated by sperm from other related species. Surprisingly, natural populations of this fish consist of a minor but significant portion (approx. 20%) of males. As different clones with specific phenotypic and genetic characteristics have been found, and RAPD markers specific to each clone have recently been identified, this fish offers many advantages for analyzing whether or not genetic recombination occurs between different clones. In this study, artificial propagation was performed in clone F and clone D. Ovulated eggs from clone F were divided into two parts and respectively inseminated with sperm from a clone D male and from a red common carp (Cyprinus carpio) male. The control clone D individuals were selected from gynogenetic offspring of clone D activated by sperm of red common carp. The phenotype and sex ratio in the experimental groups were also observed. Using RAPD molecular markers, which allow for reliable discrimination and genetic analysis of different clones, we have revealed direct molecular evidence for gonochoristic reproduction in the gynogenetic silver crucian carp and confirmed a previous hypothesis that the silver crucian carp might reproduce both gynogenetically and gonochoristically. Therefore, we conclude that the silver crucian carp possesses two reproductive modes, i.e., gynogenetic and gonochoristic reproduction. The response mechanism of two reproductive development modes may be the first discovery in vertebrates. Additionally, we discuss the evolutionary implication between gynogenetic and gonochoristic reproduction modes and the contribution of the minor proportion of males to genetic flexibility in the gynogenetic silver crucian carp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002390010113
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Numerical Analysis of Stress Concentration for Brittle Matrix Composites (2000)
    Springer
    Applied composite materials 7 (2000), S. 39-49 
    Details
    ISSN: 1573-4897
    Keywords: numerical analysis ; stress concentration ; brittle matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A FEM numerical model is constructed of SiCf/LASIII glass-ceramic uni-direction plate under tension loading. The smeared crack method is used to deal with the failure point of fiber and matrix elements. The solution of the model gives the distribution of meso-stress of SiCf/LASIII glass-ceramic uni-direction plate. The stress concentration factor K and the size of stress concentration effect zone are also analyzed. The average saturation cracking space is obtained by a numerical method. The mesh length of the elements is also studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008913800391
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Non-linear resonance conditions and their relationships to higher multipole fields in ion traps and quadrupole mass filters (1993)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 7 (1993), S. 920-928 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Deviations of electrode shapes from pure quadrupole systems result in the superposition of higher multipole fields onto the quadrupole field. Non-linear resonances are generated due to these higher multipole fields. These non-linear resonances can be thought of as internal resonances, which must fulfil appropriate conditions. In this paper, general non-linear resonance conditions for a time-variable, three-dimensional, non-linear quadrupole system are derived, using previously described methods. The occurrence of resonances depends on the electrode shapes of the non-linear quadrupole systems which control the weight factors of the higher multipole fields. With special electrode shapes, for example shapes with symmetry, the resonance effects are reduced. Different higher multipoles (for example, octopoles and dodecapoles) generate non-linear resonances which fulfil different and/or the same resonance conditions. Each resonance condition can be described by resonance lines within the stable regions of the stability diagram. Resonant ion motion possesses the characteristic that groups of ion frequencies are simultaneously resonant. These properties are analyzed and corresponding results are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290071013
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Saturation effects on ultraviolet resonance Raman intensities: Excimer/YAG laser comparison and aromatic amino acid cross-sections (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 435-440 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Substantial saturation effects are noted for resonance Raman (RR) bands of the aromatic residues in cytochrome c (excited at 230 nm) with an H2 Raman-shifted YAG or a frequency-doubled excimer-pumped dye laser. At a given average power, saturation is much lower for excimer than for YAG excitation because of the longer pulse and higher repetition rate of the excimer laser. The signal quality at low average power is significantly higher for the excimer-excited spectra. Ultraviolet RR cross-sections have been redetermined for aqueous phenylalanine, tyrosine and tryptophan at a series of wavelengths from 240 to 192 nm. The excimer laser was used at 209 nm and longer wavelengths, and in addition deconvolution techniques were applied to better define the individual RR bands. These improvements led to quantitative changes in the cross-section values from those reported previously, but the interpretation of the excitation profiles in terms of excited-state properties of the aromatic residues remains unchanged.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250210709
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Surface-enhanced Raman scattering of CO2 dissolved in aqueous colloidal solutions of silver and gold (1995)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 26 (1995), S. 959-962 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The observation of surface-enhanced Raman scatterings (SERS) from CO2 molecules dissolved in aqueous solutions of silver and gold colloids measured with 850 nm near-IR excitation is reported. Different types of surface enhancement and surface-enhanced Raman spectra were observed. The SERS spectrum of CO2 on colloidal gold is in good agreement with the spectrum of CO2 dissolved in water. Two different types of SERS spectra were found for CO2 on colloidal silver. They can be assigned to physisorbed and/or weakly chemisorbed CO2 molecules and to strongly bonded CO2 - negatively charged surface radicals, respectively. The enhancement factor for the stretching mode of carbon dioxide is estimated to be of the order of 102-104, depending on the kinds of metal and types of adsorption, which demonstrates that SERS on colloidal silver or gold particles in solution offers possibilities for detecting CO2 dissolved in liquids at low concentrations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250261006
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    Paper (German National Licenses)
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